Frost dates for Dover, DE
At Dover, the median last spring frost (32°F) is Apr 4 and the median first fall frost is Nov 4, for a typical growing season of 214 days. For a 90% chance that the last frost has passed, wait until Apr 17. Nearby ZIP codes are in USDA hardiness zone 7b.
- Apr 4Last spring frost (median)50% chance of 32°F after this date
- Apr 17Safer planting date10% chance of 32°F after this date
- Nov 4First fall frost (median)50% chance of 32°F by this date
- 214 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | Apr 3 | Apr 17 | May 5 |
| 32°F | Mar 22 | Apr 4 | Apr 17 |
| 28°F | Mar 8 | Mar 25 | Apr 5 |
| 24°F | Feb 26 | Mar 13 | Mar 27 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Oct 12 | Oct 25 | Nov 6 |
| 32°F | Oct 23 | Nov 4 | Nov 18 |
| 28°F | Nov 3 | Nov 16 | Dec 3 |
| 24°F | Nov 11 | Nov 30 | Dec 20 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 169 days | 191 days | 210 days |
| 32°F | 195 days | 214 days | 234 days |
| 28°F | 217 days | 238 days | 261 days |
| 24°F | 239 days | 263 days | 288 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 19902 | 7b | 5 to 10°F | 4 km |
| 19901 | 7b | 5 to 10°F | 5 km |
| 19904 | 7b | 5 to 10°F | 8 km |
| 19962 | 7b | 5 to 10°F | 9 km |
| 19936 | 7b | 5 to 10°F | 11 km |
| 19979 | 7b | 5 to 10°F | 12 km |
| 19934 | 7b | 5 to 10°F | 13 km |
| 19946 | 7b | 5 to 10°F | 13 km |
| 19953 | 7b | 5 to 10°F | 16 km |
| 19955 | 7b | 5 to 10°F | 16 km |
| 19977 | 7b | 5 to 10°F | 17 km |
| 19943 | 7b | 5 to 10°F | 18 km |
| 19964 | 7b | 5 to 10°F | 20 km |
| 19938 | 7b | 5 to 10°F | 21 km |
| 21649 | 7b | 5 to 10°F | 24 km |
| 21636 | 7b | 5 to 10°F | 29 km |
| 19734 | 7b | 5 to 10°F | 29 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USC00072730, at 39.1467, -75.5056, elevation 9 m (30 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 79.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Greenwood 2ne (37 km)
- Lewes (50 km)
- Georgetown Sussex Co Airport (52 km)
- Wilmington New Castle Co Airport (59 km)
- Newark Ag Farm (62 km)
- Wilmington Porter Rsch (70 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.